In recent years surgery has markedly advanced through the performance of laparoscopic and endoscopic surgical procedures such as cholecystectomies, gastrostomies, appendectomies, and hernia repair. These procedures are accomplished through a trocar assembly, which is a surgical instrument used to puncture a body cavity. The trocar typically contains a sharpened obturator tip and a trocar tube or cannula. The trocar cannula is inserted into the skin to access the body cavity, by using the obturator tip to penetrate the skin. After penetration, the obturator is removed and the trocar cannula remains in the body. It is through this cannula that surgical instruments are placed.
One surgical instrument that is commonly used with a trocar cannula is a surgical clip applier for ligating a blood vessel, a duct, shunt, or a portion of body tissue during surgery. Most clip appliers typically have a handle with an elongate shaft having a pair of movable opposed jaws formed on an end thereof for holding and forming a ligation clip therebetween. The jaws are positioned around the vessel or duct, and the clip is crushed or formed on the vessel by the closing of the jaws.
In many of the prior art clip appliers, the feeding and forming mechanisms require precise timing and coordinated movement of components to operate. This need for precise timing and control has resulted in the need for complex mechanical designs, thereby increasing the cost of the clip appliers. Many prior art clip appliers also use a spring-loaded clip advancing assembly to advance one or more clips through the shaft of the device. As a result, the jaws must contain a mechanism for preventing accidental projection of the clip from the device before the clip is formed. Other drawbacks of current clip appliers include the inability to handle an overload applied to the jaws by the trigger under a variety of conditions. Many devices require full closure of the jaws, which can result in overload on the jaws when the vessel or duct positioned therebetween is too large to allow full closure, or when a foreign object is positioned between the jaws.
Accordingly, there remains a need for improved methods and devices for applying surgical clips to vessels, ducts, shunts, etc.